Use of helical coil in vending machines as a means for transporting an item to be vended from a location within the machine to a point of discharge from the machine, by rotation of the vending coil has long been known. See for example U.S. Pat. No. 3,269,595. Typically, the vending coil has been used in conjunction with a horizontal support tray, wherein the item to be vended is placed within the windings of the vending coil and is supported by the tray. By rotating the vending coil, the item to be vended is longitudinally advanced along the tray, under force from the windings of the vending coil until it reaches the front end of the tray. Upon further rotation of the vending coil, the item to be vended is forced over the edge of the tray and falls into a discharge bin.
Early prior art vending machines of this type were configured to mount the support trays within the helical coil. This configuration, however, was particularly susceptible to problems resulting when the package to be vended got caught between the vending coil and the tray. Upon reaching the front edge of the tray, rather than falling into the discharge bin, the items so caught would hang-up at the front end of the vending coil, thus jamming the coil discharge mechanism. Various techniques have been used to eliminate this type of problem. For the most part, such techniques have incorporated means for supporting the vending coil above the tray so as to prevent the items being vended from getting caught between the vending coil and the tray. Further, to alleviate the jamming problem at the discharge end of the coil, most prior art techniques included extending the length of the vending coil significantly past the end of the support tray.
However, such prior art techniques have caused problems of their own. The coil support means have typically taken up space within the windings of the vending coil and have necessitated using large support members, requiring significantly more material, and thus increasing the cost of the machine. Further, such techniques have not totally solved the problem of items being caught, since oftentimes the items being vended will still lodge between the vending coil and the support apparatus itself, thus jamming the coil discharge apparatus. The present invention provides apparatus which minimizes the above problems associated with prior art vending machines.
Another disadvantage to many of the helical coil type vending machines of the prior art is the incapability in such machines to interchange their coils. If maximum use is to be made of available tray area, differently sized coils are required for items having different package sizes. The present invention contemplates the use of at least two basic coil sizes, one for items having larger, bulkier packages such as pastries and potato chips, and a second for smaller less bulky packages of items such as candy bars.
Still another disadvantage of the helical coil vending machines of the prior art is that with such devices, upon reaching the discharge end of the tray, the item to be vended does not always fall freely from the tray. This is particularly troublesome with items having a relatively tall package dimension. When such packages are slowly pushed forward by the helical coil and dropped over the edge of the support shelf, they tend to tip forward, rather than falling straight down, and oftentimes become wedged between the outer cabinet of the machine and the leading edge of the support tray. Such a jam typically requires maintenance and, denies the purchaser of that item for which he has paid. The present invention solves the problem by providing a positive item ejection apparatus.